Enhancing Colorectal CA Screening through Learning Teams Context: Primary care practices have ongoing access to the majority of the U.S. population, making them ideal for the early detection of colorectal cancer. However, due to their broad focus and competing demands, primary care practices often fail to translate evidence-based screening strategies into practice. Background: Based on more than 10 years of NCI and AHRQ funded observational and intervention research, we developed an organizational change model that understands practice change as a complex and dynamic multi-dimensional process. We have translated this model into an intervention strategy that incorporates a multi-method assessment process (MAP) for understanding the unique barriers, opportunities and complexity of diverse primary care practices and a Reflective Adaptive Process (RAP) that involves patients, office staff, and physicians. Participation in learning collaborative enhances motivation and expands available options for change. This MAP/RAP-learning collaborative intervention targets both overall practice capacity to change and colorectal cancer screening. Purpose: This study evaluates whether the innovative MAP/RAP intervention enhances and sustains rates of colorectal cancer screening in primary care practice. Methods: A group randomized clinical trial of 30 primary care practices representing diverse patient populations and payment systems will be conducted. MAP at each practice will identify features that foster and/or impede adherence to cancer screening guidelines. An RAP team of clinicians, staff, and patients will then implement tailored improvements that target the whole practice. Participation in a practice learning collaborative will reinforce the RAP process and assist practices in identifying options for enhancing cancer screening. Rates of colorectal cancer screening will be compared for intervention and control practices at baseline, 12, and 24 months. Multilevel modeling will be used to control for clustering and any baseline differences. A comparative case study process analysis will identify features of the intervention associated with success. These insights will be incorporated into a refined intervention for the control group (delayed intervention), and evaluated in a pre/post design. Significance: This tailored multi-faceted intervention is highly likely to result in sustainable increases in rates of colorectal cancer screening across multiple practice settings. Practice improvements will be translatable into new efforts that increase cancer screening in the settings where the majority of Americans receive most of their medical care.